Dietary guanidinoacetate reduces spaghetti meat myopathy risk in the breast muscle of broiler chickens

The global demand for white chicken meat along with the increase in the occurrence of growth-related breast muscle myopathies (BMM) [namely white striping (WS), wooden breast (WB), and spaghetti meat (SM)] highlight the need for solutions that will improve meat quality while maintaining the high productivity of modern broilers. Guanidinoacetate (GAA), a precursor of creatine, is used as a feed additive and has previously shown the potential to affect the quality of breast meat. This study investigated growth performance, meat quality and the risk ratio for the development of BMM in broilers assigned to 2 dietary treatments: control (CON) group, fed a commercial basal diet, and supplemented GAA (sGAA) group, receiving the control diet and supplemented on top with 0.06% GAA. Growth performance indicators such as body weight, daily weight gain, daily feed intake, feed conversion ratio and cumulative feed conversion ratio were recorded on a pen basis. As a trait affecting animal welfare, the occurrence of foot pad dermatitis was also evaluated. At day 43, birds were processed, and breasts were scored for the incidence and severity of BMM (n = 166 and 165 in CON and sGAA groups, respectively). Quality traits (ultimate pH, colour) and technological properties (drip and cooking losses, marinade uptake, shear force, and oxidation levels of the lipid and the protein fractions) of breast meat were assessed in both treatments on samples not showing any macroscopic sign of BMM (n = 20 breast fillets per group). Data of myopathy risk ratio were analysed as the risk for each group to develop WS, WB, and SM myopathies. Our results show that while sGAA and control groups did not differ significantly in growth performance, a remarkable beneficial effect of GAA was observed on the incidence of BMM with significantly reduced risk of sGAA group to develop SM myopathy. The risk of sGAA group to develop SM was 30% lower compared to the control (P = 0.028). Finally, a significantly lower drip-loss was observed in sGAA in comparison with control (1.78% vs. 2.48%, P = 0.020). Together, our results show that inclusion of 0.06% GAA in feed can improve the water holding capacity of meat and reduce the risk to develop SM myopathy without compromising the performance of broilers.